Improvement in printing-ink rollers



UNITED STATES E. PRATT, OF SALEM, MASSACHUSETTS.

IMPROVEMENT IN PRINTING-INK ROLLERS.

Specification forming part of Letters Patent No. 21,148, dated August10, 1858.

To all whom it may concern:

Be it known that I, ELISHA PRATT, of Salem, in the county of Essex andState of Massachusetts, have invented certain new and usefulImprovements in the Manufacture of Printers inking-Rolls, of which thefollowing is a full, clear, and exact description.

Printers rolls for inking types have heretofore been made of a compoundof glue and molasses; but rolls thus made are liable to many objections,among which are the followin g: First, in cold weather the rolls hardenand stiffen, and time is lost in warming them before they can be used;second, in warm weather the rolls bag, and often work loose from thecore; third, the ink in time extracts the molasses from the compound,leaving the glue, which then soon hardens and cracks. These objectionsrender the frequent renewal of the rolls necessary, and their removalhas long been considered a great desideratum. Fourth,

they are also exceedingly liable to sour and spoil, particularly'in warmweather, whereby they are soon renderedworthless.

To remedy the first three of the above difficulties is the object of thefirst part of my invention, which consists in the incorporation ofcertain oily or resinous substances with the materials heretoforeemployed, by which the roll is rendered more permanently elastic, and isprevented from hardening in cold weather or softening and bagging in hotweather to so greatan extent, while the molasses is also prevented fromworking out and leaving the glue, as before mentioned.

The second part of my invention has for its object to remedy thefourthobjection above enumerated-viz., the souring or spoiling of thematerial; and this I accomplish by the incorporation of an alkali withthe other in gredients, by which their acidity is corrected and they arerendered less liable to spoil or fer- Inent.

That others skilled in the art may understand and use my invention, Iwill proceed to describe the manner in which I have carried out thesame.

The following are the ingredients which I use to make my improved in king-rolls, and the proportions in which I prefer to use them, although theexact quantities may be somewhat varied without departing from thespirit of my invention: four pounds glue; two quarts mo- 1asses,sirup,or honey; one gill rosin-oil in which two ounces of rosin has beenmelted; two ounces gum-shellac in a suficient quan tity of alcohol todissolve it one table-spoonful of saleratus or sal-soda.

The following is the manner I have adopted of incorporating the aboveingredients: The glue is soaked in water for a few hours to soften it,and then boiled in a vessel surrounded with water (like an ordinaryglue-pot) until it has become liquid-say for two or three hours. I thenadd the molasses, sirup, or honey and stir it in; then the saleratus orsal-soda, previously dissolved in water, the rosin-oil, in which therosin has been previously melted, and the gum-shellac in alcohol,stirring them all into the mass, which is caused to effervesce by thesaleratus or soda. I then boil the whole for one or two hours, until theeifervescence ceases and the mass assumes a smooth surface withoutbubbles, when it is ready for pouring into the molds. A core is place inthe mold and the composition is poured in and cools around the core,adhering to it in the ordinary manner of making these rolls. As some ofthe rosin-oils of commerce are more limpid than others, they willrequire to have added to them a larger proportion of rosin than thoseoils which are more viscid.

I will here mention some of the advantages which an inking-roll made inthe above manner possesses over those of the ordinary construction. Itis comparatively free from airholes, and consequently more uniform inits consistency. It will not shrink or crack to the same extent. It willnot be so apt to bag or start from the core, and is not so much atfootedby the changes of temperature, and owing to the above characteristics itis far more durable than thosevheretofore employed.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The employment of an alkali in the manufacture of inking-rolls, inthe manner and for the purpose substantially as herein set forth.

2; The use of rosin-oil, rosin, and shellac, in combination withtheothermaterialsemployed, in the manner set forth, for the purposespecified.

ELISHA PRATT.

